To add to what every other reply is telling you, I ignored the census form they mailed to my house. A month later, some guy stopped by and asked me the question

To add to what every other reply is telling you, I ignored the census form they mailed to my house. A month later, some guy stopped by and asked me the questions in person. People camping in semi-remote places and those living out of their cars/ blending into society are probably missed, but that is a small proportion of the population.